Storage medium



1957 R. B. JOHNSON 2,810,900

STORAGE MEDIUM Filed April 14, 1954 F/GQI FIG. 2

IN V EN T OR. REY/v0.10 B. JbbA/SO/V BY 7 FIG. 3 d

AGENT Unite States Patent Patented Oct. 22, 1957 2,810,900 STQRAGIE MEDIUM Reynold B. Johnson, Palo Alto, Calif., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York Application April 14, 1954, Serial No. 423,193

7 Claims. (Cl. 340-173) The present invention appertains to storage media and relates more particularly to coherers utilized as a storage medium.

It will be recalled that, when a coherer is cohered, a low resistance metallic path or chain is created between the terminals thereof through the coherer powder. The particles of powder which form the chain adhere to each other and the chain will remain intact until the coherer is jarred sufficiently to break it. It has often been found that the coherer chain is only partially disintegrated when broken by the application of a mechanical shock and, as a result, the reliability of a coherer is reduced after continued use thereof, since, as the number of partial chains in proximity to the electrodes of a coherer is increased, the voltage necessary to fire that coherer is reduced. This is due to the fact that the firing voltage of a coherer is directly proportional to the electrode spacing, and, as the number of partial chains in proximity to a set of electrodes is increased, the effect is the same as if the space between its electrodes were reduced. Additionally, since certain coherers are used more frequently than others in many types of installations, the firing voltage of these coherers is reduced in a greater proportion than it is for the less frequently used coherers, and t .erefore the firing voltage of identical coherers may vary widely. For these reasons, coherers used in the past have been found unreliable and have proven unsatisfactory for storage purposes.

It is one object of the present invention to provide an improved coherer structure.

Another object is to provide a coherer structure wherein the problems outlined above are minimized.

A further object is to provide a coherer structure adapted for use as a storage medium.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode which has been contemplated for applying that principle.

In the drawings:

Fig. l is a plan view of the novel coherer structure.

Fig. 2 is a vertical section taken along line 2-2 of Fig. 1.

Fig. 3 is a bottom view of the structure of the invention.

The present invention is adapted for use, for example, with a storage device such as is disclosed in the copending application Serial Number 418,101, filed on March 24, 1954, in the name of Louis D. Stevens and entitled Storage Mechanism. It should be understood, however, that utilization of the present structure is not limited to this application but that it is equally suited for use with a wide variety of different types of storage devices.

Referring to the drawings, the coherer structure comprises a disc (Fig. l) of any suitable non-conducting material, such as Lucite. A circular trough 11 is provided within the upper surface of the disc 10, and mounted adjacent the innermost wall of the trough 11 is a ring 12 composed of brass or the like. The ring 12 functions as a coherer terminal common to a plurality of coherers, as will become clear hereinafter.

The trough 11 is partially filled with a finely divided metallic powder 13, having the desired physical properties of a coherer powder, and a plurality of small diameter rods or pins 14 are provided to extend downwardly through the powder 13, through the bottom of the trough 11 and exteriorlyof the disc 10. In the present embodiment, fifteen pins 14 are shown, and each of these pins forms the second terminal of one coherer. Any convenient number of such pins may be provided, however, the number thereof determining the storage capacity. Each of the pins 14, as well as the common terminal 12, is provided with wiring 15 for connection to appropriate circuitry, as may be desired.

The disc 10 is secured to a hub 16 by studs 17, and the hub is keyed to a shaft 18 by a set screw 19. The shaft 18 is journalled in and extends downwardly through a collar 20, which is formed integrally with a support 21, to permit rotation of the disc 10, hub 16 and shaft 18 relative to the support 21. An arm 22 is keyed to the shaft 18, near the lower end thereof, by a set screw 23, and one end 24 of the arm 22 is spring urged against a stop 25 by a coil spring 26, the spring being mounted in tension between the arm 22 and a stud 27 secured to the base plate 21.

The other end 28 of the arm 22 is pivotally secured to a link 29 which, in turn, is pivotally connected to the armature 30 of a solenoid 31. The solenoid 31 is mounted on the lower face of the support 21 by studs 32 and is provided to decohere the coherers when the information stored therein is to be erased. Energization of the solenoid 31 attracts the armature 30 thereof and the arm 22 is rotated thereby a short distance in a counterclockwise direction as indicated in phantom lines (Fi 3). When the solenoid 31 is tie-energized, the arm 22 is released and the spring 26 is arranged to swing the end 24 of said arm against the stop 25, thereby mechanically jarring the coherer structure and applying a rotary shock to the coherer powder 13. Energization of the solenoid is accomplished by placing a suitable voltage across the coil terminals 33 thereof.

When utilizing the structure of the invention for storage purposes, the coherers are selectively subjected to a cohering voltage in the manner taught in the aforesaid copending application or by any other convenient or desired method. The potential necessary to cohere a coherer is determined by the physical properties thereof, as is well known to those familiar with coherers, such properties including the electrode spacing and the type and mesh of the powder utilized. The actual physical properties required for a particular embodiment is determined by the voltage range within which it is desired to operate. It has been found, for example, that a coherer having an electrode spacing of 0.1 inch and utilizing a bronze sphere powder which passes through a mesh screen but will not pass through a 200 mesh screen will always fire at volts and will never fire at 50 volts. (These figures are approximate only and may be caused to vary if either extremely long or extremely short voltage pulses are applied to the coherers. The actual electrode spacing to be utilized under the desired operating conditions may probably best be found experimentally.)

To enter information into the coherers for storage, it is only necessary to apply a voltage sufiicient to cause co herence across the selected terminal pins 14 and the common terminal 12. When the coherers cohere, a low resistance path is created between the corresponding pins 14 and the common terminal 12 which may be utilized to effect read-out. To erase information stored in the coherers, the solenoid 31 is energized momentarily to theretion, therefore, to

by apply a rotary shock ,to the'coherer powder, as de-- powder caused by successive 1 complete disintegration of cohered chains before they'are again subjecting to a cohering force,'and' thereby increases the reliability .of the coherer. 1

While there have been shown ancldescribed and pointed out the fundamental novel features'of the invention as applied to a preferred embodiment, it willbe understood that-various omissions and substitutions and changes in the form and details of the 'device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intenbe limited only as indicated'by the scope of the following claims.

What is claimed is: 1

1. A storage medium comprising means defining a reentrant cavity, a conductor disposed within said cavity, a plurality of electrodes disposed within said'cavity and spaced from said conductor, a powder within said cavity extending between said electrodes and said conductor, said powder including particles adapted to cohere and toform low resistance chains between said electrodes and' said conductor in response to a voltage applied between said electrodes and said conductor, and means for applying a shock to said powder for breaking said lowresistance chains and for progressively advancing said, powder through said cavity. V 1

2. Astorage medium comprising a circular container, a portion of said container being composed of a conducting material which forms a first electrode, a plurality of conductors'disposed within said container andospaced from said first electrode, a powder within said container extending between said first electrode and said conductors,

said powder containing metallic particles adapted to'cohere to form a low resistance pathrbetween said first electrode and one of said conductors in response to a voltager'placed. thereacross, and means for applying a rotaryshock to said powder for breaking said .paths whereby said powder is movedrprogressively through said 7 container from one of said conductors toward anadjacent conductor.

, '3.-A storage medium comprising means definingia circular trough, a conductor disposed within said trough, a

plurality of electrodes disposed within said trough and spaced from said conductor, a powder within said trough extending between said electrodes and said conductor, said powder containing finely divided metallic particles adapted to cohere to form low resistance chains between said electrodes and said conductor in response to a voltage placed thereacros's, meansfor selectively subjecting said electrodes and saidconductor to said voltage, and'means for applying a rotary shock to said powder for breaking saidtlow resistance chains whereby said powder is progressively advanced around said trough. p

4. A storage device comprising a body member having a reentrant trough therewithin, means for supporting said member intermediately of the boundaries defined by said trough, a finely divided metallic powder within said trough, a conductor extending into said powder, a plurality of" independent electrodes extending into said powder. and spaced from saidconductor, means for placing a voltage across a selected one of said electrodes and said conductor for cohering the powder. therebetween, and means for applying a'rotary shock to said powder for decohering said powder and for advancing said powder through said trough. a I 7 V V a 5. The invention set forth in claim 4 wherein the deco hering and advancing means includes means for angularly displacing said supporting means.

6. A storage device comprisingmeans-defining a reentrant trough, a powder'contained within said trough, a plurality of electrodes extendinginto said 'powdensaid powder containing metallic particles adapted to cohere e and to form a conductive path between two of said electrodes when a voltage is applied-thereacross, andmeans for decohering' said powder by breaking said conductive path in such a way that said powder is advanced through said trough. 1 .7 g

7. A storage. device comprising a body'member, means 7 defining a reentrant trough within said member, a finely divided metallic powder within said trough, a conductor extending into said powder, a plurality-of independent electrodes extending into said powder and spaced from a said conductor, means for selectively subjectingsaid electrodes and said conductor to a voltage for cohering the powder therebetween, and means for abruptly changing the angular velocity of said body member for decohering said powder and for progressively moving said powder through said trough. v V I References Cited in'theffile'of this patent v UNITED STATES. PATENTS 708,071 Pickard Sept.'2,l902 1,201,034 111 on; 10, 1916 

